1. Renewable Energy Sources
composed by
Dragica Vasileska

2. In the last 100 years, the Earth warmed up by ~1° C
Source: Steven Chu
100 years is nothing by geological time scales!

3. Can we predict the past?
Climate change due to natural causes (solar variations, volcanoes, etc.)
Climate change due to natural causes and human generated greenhouse gases

4. CO2 Concentration, Temperature, and Sea Level
Continue to Rise Long after Emissions are Reduced
Sea-level rise due to ice melting: several millennia
Sea-level rise due to thermal expansion:
centuries to millennia
CO2 emissions peak
0 to 100 years
Temperature stabilization:
a few centuries
CO2 stabilization:
100 to 300 years
CO2 emissions
Today
1,000 years
100 years

5. The possibility / likelihood of global warming is disturbing …
Chu
The possibility / likelihood of global warming is disturbing …
… but there may be a bigger problem!

6. Consumption of Energy Increased by 85% Between 1970 and 1999
By 2020, Consumption will Triple
Source: Steven Chu

7. World production of oil and gas is predicted to peak within 10 - 40 years
2010

8. Energy conservation and efficiency can buy time (a factor of ~2) but the fundamental problem remains

10. Electrical generation
Switch from petroleum to coal and natural gas
Why has hydroelectric declined?
When did nuclear go up?

11. Estimates of depletable energy resources in the U.S.
Numbers = how long it would last if all energy came from one source
Resource recoverable recoverable and hoped for
Coal
Petroleum ?
Natural gas ?
Oil shale
Conventional reactors
Breeder reactors
Fusion to 109
Geothermal surface
deep rock

12. Estimates of renewable energy
Numbers = proportion of current U.S. energy needs that could be supplied for an indefinite period.
Tidal energy
Organic Waste
Photosynthesis
Hydropower
Wind Power
Solar radiation

13. Today: Production Cost of Electricity
(in the U.S. in 2002)
25-50 ¢ 5 10 15 20 25
Coal
Gas
Oil
Wind
Nuclear
Solar
Cost
Cost, ¢/kW-hr
6-7 ¢
6-8 ¢
5-7 ¢
1-4 ¢ ¢
Courtesy Nate Lewis

14. Energy Costs www.undp.org/seed/eap/activities/wea Courtesy Nate Lewis
$0.05/kW-hr
Europe
Brazil
Courtesy Nate Lewis

15. Potential Sources of Energy when Fossil Fuels Run Out
Magnetic Plasma Confinement,
Inertial Fusion
Nuclear Fusion
Waste &
Nuclear Proliferation
Nuclear Fission
10 TW = 10,000 new 1 GW reactors: i.e., a new reactor every other day for the next 50 years

16. We do not know how to store electrical energy on a massive scale
Solar, Wind and Water
We do not know how to store electrical energy on a massive scale
Nature has been converting sunlight, CO2 water and nutrients into chemical energy for billions of years.

17. Geothermal
Heat near surface of the earth = geysers, volcanoes, hot springs

18. Solar to Chemical EnergyCO O H 2 2 2 e e
Sugar sc M sc M
H O 2
H O 2 O 2
Photosynthesis
Semiconductor/ liquid junctions
Photovoltaic and electricity to chemical

19. Energy gained in corn ethanol production

20. Total CO2 emissions

21. From Summary of Renewable Fuel Options (NCEP)
“Unlike corn ethanol, cellulosic ethanol has potential to achieve near-zero net carbon emissions.
Cultivation of cellulosic feedstocks requires very low energy inputs and, if sustainably managed, the carbon released during fuel combustion is reabsorbed by the growth of new feedstocks.”

22. Geothermal Energy in More Details
Use heat to make steam to turn turbine for electrical generation
Note: deep hot waters are corrosive to best to inject clean water in a closed system and bring it back to the surface as steam.

23. In U.S., much done on public land = cheap
Very little potential in east and mid west

24. World wide distribution of volcanos, hot springs, etc.
Japan, Iceland,New Zealand big users of geothermal.

26. Although hot areas near surface are limited, the earth is hot everywhere if you go down far enough.

27. Bright idea. – drill deep enough to find heat
Bright idea!? – drill deep enough to find heat. Since rock is a poor conductor of heat, set off a big bomb to crack the rock and allow heat to move – then pump down water to make steam.

28. Hydropower in More Details

29. Hydropower = dams
Not much used in world, why??

30. Norway, Zambia, Ghana big users

32. Most unused hydropower in U.S. = Alaska,
In World = Canada, Russia

33. Problems with hydroelectric
Location = unused rivers are in extreme north or low population areas
Competition with recreational uses (U.S.) and environmental concerns
Hard to build dams in populated river valleys
Siltation of dams – limited life.

34. Tidal Power
In areas of large tides
Anywhere – build offshore dam

35. Highest tides in the world = Bay of Fundy 16 meters = 48+ feet!

36. Tidal power anywhere
No dam – but a turbine.
Problems:
Corrosion
Navigation
Appearance
Amount of energy available is low
Best tides are near poles – away from people.

37. Wind Power in More Details
Banning Pass

38. Wind Power Generation

39. Best wind location = Aleutian Islands, why no wind development there?

40. Best U.S. localities
Midwest, mountains
And coastal areas.

42. Netherlands = coastal development

43. England = off shore

44. Wind energy problems Location – near population center
Bird migration –
Visual
Must be coupled with other sources of electricity (intermittent supply)

45. Solar Energy in More Details
1. Solar Thermal

46. At focal point = heat liquid – steam to turn turbine

48. Solar Resource for a Concentrating Collector

49. Big Plants

50. 2. Solar Photovoltaics

51. ‘hard’ vs ‘soft’ energy paths
Big plants
Centralized production
Soft =
Decentralized
units per household

52. Big Plants

53. Decentralized
Energy efficient house; wind power on roof. Solar panels for heat and electricity.

54. Solar electricity generation

55. Solar water heating solar air heating

56. Solar house problems The Los Angeles air = smog
Retrofitting- very expensive
Hard for big hotels, Walmarts, etc.

57. Solar house economics Add $16,000 to price of house
Pay back - $1500 per year in energy costs
15 years to break even
Federal tax incentive; 40% of investment can be written off. Discontinued in 1986
City of Claremont – solar energy ordinance. 60% of hot water – solar
Exceptions for equivalent savings of energy = Colleges approach. Why not trust solar?